Lock.



A. A. OLSON L G. H. BLOOD.

LOCK.

APPLICATION FILED 111111.21, 1912.

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ALMA A. OLSON AND GEORGE H. BLOOD, OF PRESTON, IDAHO, ASSIGNORS TO NATIONAL LOCK AND MFG. CO., A CORPORATION OF IDAHO.

LOCK.

To all whom it may concern Be it known that we, ALMA A. OLSON and GEORGE H. BLOOD, citizens of the United States, and residents of Preston, Idaho, have invented certain new and useful Improvements in Locks, of which the following is a specification.

Our invention relates to an improved form of lock and key therefor.

A principal object of the invention is to make it extremely diiiicult and practically impossible to pick the lock or to operate it without the special key provided for it.

Another object is to provide the bolt 4with a plurality of levers, all of which must be operated in order to shoot the bolt.

A further object is to construct the bolt and levers so that it is impossible to move the bolt unless the levers are irst moved a certain distance, and so that it is also impossible to move the bolt if the levers are moved too far. y

A further object is to provide` a special key with a form of expansible bit or bits which operates simply and is easy to manufacture and to construct the lock so that it coperates with this form of key-bit.

A further object is to construct the lock and key so that it is easy to make slight changes in individual products so that a certain key will only actuate its own particular lock.

lVe will now describe an exemplifying form of the invention as shown in the accompanying drawing. It is to be understood that the invention is capable of embodiment in many other forms.

Figure 1 is an elevation of a lock with the cover plate removed. Fig. 2 is a vertical section on the plane of the keyhole. Fig. 3 is a fragmentary view of the bolt- Vreverse and key, showing the levers in the released position and the bolt ready to be with one of the levers removed to clearly show the remaininglever in proper position to release the bolt. Fig. 5 is a similar view showing the lever in position to hold the bolt in its extended or locked position.' Fig. G is a detail enlarged view of the key, a part being shown in section. A

Reference character 1 designates the bolt provided with slot 2 embracing the fixed pin 3. The boltJ also has the arc-'like segment 4f and notch 5 for engagement by the fixed part of the key-bit. One or more levers 6 Specication of Letters Patent.

Application filed March 21, 1912.

Fig. 4 is a similar viewv Patented Feb. 10, 1914. serial No. 685,248.

are provided. Usually. there are two, one on each side of the bolt as shown. The levers are pivoted on the pin 3. rl`he lever springs may differ greatly in form and arrangement but, in the convenient form of the invention, they are simply supported by a stud 10 in the casing and have their active ends llengaging upon lugs 12 of the levers. The opposite ends of the springs may be placed against the pin 13 in the casing, which may also support the latch spring 14, as shown. Near one end,the bolt is provided with notches 15, 16, and near the other end it is provided with notches 17, 18, separated by lug 19. Each of the levers has at one end an inward projecting tooth 20 to cooperate with notches 15, 16, and at the other eizld a tooth 21 to'coperate with notches 1 18. I

It will now be evident that 'as best seen in Fig. 4, the bolt cannot be moved away from either its inner or outer position unless both of thellevers are held in practically the exact position shown in Fig. 4 with their teeth 20, 21, both out of register with the adjacent notches 14, 15 and 17, 18. Both oi' the levers being so held,the bolt may be shot in or out. VIf the levers are then free to move under the influence of their springs, or if only one of them so moves, itstooth 21 will engage in notch 17 supposing the bolt is inward and in notch 1S supposing the bolt is outward, and in either case the bolt cannot be shot untilthe lever is properly raised. At the same time,` in raising the levers to permit the bolt to b shot, if either or both of them Vis moved too far, the tooth 2O will enter either notch 15 or notch 16,' and prevent movement of the bolt. It is exceedingly difficult and practically impossible, therefore, to pick this lock because without the key specially provided each of the levers must be manipulated by some wire or other implement and held at exactly the proper position against the spring'pressure and at the same time a third wire or other instrument must be properly manipulated to shoot the bolt. This complicated operation, it is evident, is practically impossible, especially since the lock presents no outwardevidence of being different from an ordinary lock and gives no indication as to ho-w it should lbe manip-- ulated. The diliiculty of picking, it will be evident, is increased by providing independent springs for the levers, but when it is considered unnecessary to do this the construction may be somewhat simplified by connecting the active ends 11 of the lever springs in the obvious manner.

The special key provided to operate the lock comprises an ordinary shank 30 and bit 3l, which may be varied greatly in shape, and also two movable bits 32 which in a simple and advantageous form orl the invention consist simply of short round rods inserted in the holes in the outer portion of the bit and movably secured in position by the pressure of a spring compressed between the two rods in a transverse chamber or bore in the bit. In the casing on the bottom and on the cover are provided two cams 35 preferably of oval shape as shown, so that a comparatively straight portion 36 is provided to hold the movable bits in extended position as they engage the levers during the movement of the bolt.

Vhen the key is inserted in the lock, the movable bits are in their inward position as shown in Fig. l. As the key is revolved, the inner ends of the bits strike the cam and are pushed out so that as the fixed bit approaches the bolt notch 5, the movable bits raise the ends of the levers and release the bolt and hold the levers in released position until the bolt is shot. Fig. 8 shows the key midway in its movement with the movable bits resting upon the cam and holding the levers in released position and with the fixed bit engaging the bolt notch after having removed the bolt halt-way out. This movement is continued until the iixed bit approaches the bottom 40 of the casing adjacent to the key-hole. The outer ends of the movable bit then encounter the side or bottom wall of the casing and are pushed in again until they take the position shown in Fig. l, whereupon the key may be removed from the lock and is ready for re-insertion to withdraw the bolt. It will be evident that the movable bits are made just the proper length to properly engage the cam and at the same time to move the levers to the exact free position, and it will also be evident that by slight-ly changing the shape of one or both oi' the cams or the length of one of the movable bits and correspondingly changing the shape or arrangement of the corresponding lever, the lock may be made so that it can be opened only by the particular key designed for it.

Having described our invention, what we claim is l. In a lock, the combination of a casing having a keyhole, a bolt, a lever-tumbler therefor, a pivot for the lever-tumbler, the bolt and lever-tumbler being provided at each side of the pivot with complemental notches and projections whereby the bolt is released from the lever-tumbler when the latter is .moved a certain distance but is reengaged by the lever-tumbler when the latter is moved more than said certain distance, a key, an extensible bit carried thereby, the bit being movable approximately at right angles to the key axis, a cam adjacent to the keyhole for engaging the inner end oi' said bit and throwing it out by the rotative movement ot' the key, the casing being constructed and arranged to engage the outer end of said bit and retract it to permit withdrawal of the key.

2. In a lock, the combination ot' a casing, a bolt therein, a pin passing through a slot in said bolt, bolt lever-tumblers, one on each side ot' said bolt and pivoted on said pin, the lever-tumblers being provided with projections at each side of said pin, and the bolt being provided with complemental notches for engagement by said projections in both the inward and outward positions of the bolt, the bolt being provided with a key socket and the lever-tumblers being provided with extensions adjacent to said socket, a key having two extensible bits for engaging said lever-tumbler extensions, and cams carried by the casing adjacent to the keyhole acting upon rotary movement of the key to extend the bits and cause them to move the lever-tumblers to released position while the key engages the bolt socket to shoot the bolt.

3. In a lock, the combination of a bolt, a plurality of cooperating retaining levertumblers, a spring for each lever-tumbler, a key having a plurality of expansible bits and cams adjacent to the key-hole one for each bit, the cams, bits and lever-tumblers being relatively constructed so that in one rotation. of the key the bits are first extended, then actuate the lever-tumblers to release them while the bolt is shot, and the bits are then retracted to permit the key to be withdrawn.

4f. In a lock, the combination of a casing having a keyhole, a plurality of cams carried by the casing adjacent to the keyhole, a bolt, a plurality of lever-tumblers there- 'for having means to engage the bolt except when moved to a certain free position, a key, and a plurality of extensible bits carried by the key adapted to be severally engaged by said cams during the rotary movement ot the key to extend said bits.

In a lock, the combination of a casing having a keyhole, a plurality of cams carried by the casing adjacent to the keyhole, a bolt, a plurality of lever-tumblers therefor having means to engage the bolt except when moved to a certain free position, a key, and a plurality of extensible bits carried by the key adapted to be severally engaged by said cams during the rotary movement of the key to extend said bits, said bits being adapted severally to raise the leverl tumblers each to its free position and then engage and shoot the bolt.

6. In a lock, the combination of a casing haring a keyhole, a Cam carried by the casing adjacent to said key-hole, a bolt, a levertumbler therefor, a key, a rigid bit Carried by the key to engage the bolt, and an eX- tensible bit carried by the key adapted to be engaged and extended by said cam so as to engage the levertu1nbler- 7. In a lock, the Combination of a Casing having a keyhole, a Cani Carried by the casing adjacent to the keyhole, a bolt, a levertinnbler therefor having means to engage the bolt except When moved to a certain denite free position, a key, a rigid bit earthe cam being arranged substantially parallel to each other so that the lever-tumbler is raised and held in the same position throughout a large part of the rotation of the key.

ALMA A. OLSON. GEO. H. BLOOD. Witnesses: GEORGIA MAUGHAN,

MARTHA SUTHERLAND.

y(Jopie: of this patent may be obtained for five cents each, by addressing the Commissioner ot Patent, Washington, I). C. 

